I second that. In addition to filing flight plans it would be important to keep in touch with air traffic control regularly, particularly when entering a country, and also monitor guard if capable. There is not that many paved airports over there so the few ones available are likely to have English-speaking people. Just make sure you double check things like the correct fuel grade, and be wary if they tell you 'don't worry, everything will be fine'.

About the regulations, they should all follow ICAO procedures for international flights, find some resources that have all the steps and required procedures, including customs forms, security inspections, etc.

Not sure if you can get good VFR charts, in some cases I know there are available WAC and ONC charts, but getting them all the way there may be pricey, and some of the charts may be a little dated (say a decade or more?). The only place I've seen maps that could be used for VFR flight is the Air Navigation Pro app for Ipad. It has ONC charts and other maps that can be downloaded for free, and the moving map with the pink line is also nice. The app also has drawings of the restricted and prohibited airspaces, which could come handy to avoid unwanted encounters with the Tucanos.

Skyvector has a beta version of their website with international airports. By no means does it cover all of them, not even close, but can be a good guide. VFR charts for many regiosn of the world are hard to come by. Many times one is stuck with the old ONC charts that haven't been updated in decades.